Outbound route via SIP trunk does not include caller name

When connecting FreePBX to another IP PBX in the same company I use a SIP trunk connection between both systems. For incoming calls the CallerID shows as well the NUMBER and the NAME, but for outgoing calls from FreePBX the CallerID only includes the NUMBER in the SIP invite messeage. The NAME is not included, even if I check the “Intra-Company” flag in the outbound route configuration. Is this a bug or do I miss some other setting to make this work ?